空间科学学报

2400 Years and track cycles of the sun's orbital motion

Liu Fugang, Zheng Yi, Wang Jian, Luo Jinming, Bao Kunshan

2015, 35(4): 381-392. doi: 10.11728/cjss2014.04.381

Abstract(2390) PDF 5318KB(10163)

Abstract:
Through Fourier transferring of data from the planetary synodic index, it is found that the year, 10-year, 100-year, 1000-year, 10000-year and 100000-year scales of cycles have 10ⁿ multiple relationship. More interestingly, if we set the most significant period (4.96488a) on the year scale as the unit time step and put it into the equation of planetary synodic index, 2400 years cycle would be determined stably. On this basis, 2400 years cycle can be also assembled to form 100000 years and 400000～410000 years cycles of the Sun's orbital motion. This is helpful to unveil the relationship between the Sun's orbital motion and solar activity, and is significant to discuss the mechanism of climatic variation on the thousand years and orbital scales.

Comparative Study of Three AUSM Algorithms and Simulated Application on the Solar Wind

WANG Tao, LI Huichao, ZHANG Man, FU Huazheng

2015, 35(4): 393-402. doi: 10.11728/cjss2015.04.393

Abstract(1587) PDF 3814KB(1349)

Abstract:
Numerical simulation of MHD (Magnetohydrodynamics) is an important method to study solar-terrestrial physics phenomena. In this paper, three AUSM algorithms, i.e., AUSM, AUSM+, AUSMPW+, were compared in conjunction with the HDC method to eliminate the divergence of the magnetic field. The AUSM+ algorithm is found to be better than the AUSM algorithm and the AUSMPW+ algorithm through the results of Rotor example and Orszag-Tang vortex example. Further, the AUSM+ algorithm is used to simulate the coronal with a six-component grid system. The results show that this algorithm can correctly calculate the large-scale structure of the corona. Also, the HDC method can maintain the divergence-free constraint on the magnetic field.

Determination of the Kelvin-Helmholtz Wave Parameters on the Magnetopause in Single-spacecraft Observations

LIN Dong, WANG Chi, LI Wenya, TANG Binbin

2015, 35(4): 403-408. doi: 10.11728/cjss2014.04.403

Abstract(1066) PDF 1436KB(1486)

Abstract:
Kelvin-Helmholtz (K-H) waves are formed from the triggeringof the K-H instability on the magnetopause, which is a candidatemechanism for solar wind entry into the magnetosphere, especially undernorthward interplanetary magnetic field conditions. In this study, aK-H wave event was identified from the observation of probe Bof the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission on 15 May 2008. A new method to determinethe wave parameters of the K-H waves in single-spacecraft observationsis proposed. The dominant wave period is determined by three kinds ofspectrograms for three key parameters, namely the ion density, the iontemperature, and the z component of magnetic field. The phasevelocity is estimated by calculating the center-of-mass velocity of thedetected K-H vortex region. This approximation is validated bycomparison with other alternative methods. The method to determine thewave parameters is a first step to further study K-H wave properties and their relationship with interplanetaryconditions.

Numerical Simulation of Dipolarization Fronts in the Plasma Sheet of Magnetotail

SHEN Jingran, CAO Jinbin, LÜ Haoyu, FU Huishan

2015, 35(4): 409-414. doi: 10.11728/cjss2015.04.409

Abstract(1779) PDF 1493KB(1068)

Abstract:
This paper focuses on the numerical simulation of the physical and evolution features of the Dipolarization Fronts (DFs) by using the eight-wave MHD equations based on the conservation TVD scheme. Firstly, a numerical model of DFs which is produced by BBF flux is built up. It is made up of three parts, i.e., magnetotail balance model, substorm growth phase model and substorm triggering BFF model. The result of numerical simulation presents the features of the DFs caused by BBF flux. With the appearance of high speed flow, magnetic field B_z component shows the changing asymmetric bipolar structure, which means that pre-front decreases to negative while expands rapidly on the DFs. When B_z increases to its maximum, it falls and becomes stable. With the DFs moving earthward while the high speed flow heading to the same direction, B_z on the DFs changes less and less. The generations of high speed flux and the DFs make a wider differentiation in the tail. Therefore, B_z component starts sinking, which can be explained as the plasma of the earthward compression of the DFs generated by the speed differentiation.

Relationship between X-class Flares and Geomagnetic Effects

ZHU Yiting, ZONG Weiguo, PEI Shixin

2015, 35(4): 415-423. doi: 10.11728/cjss2015.04.415

Abstract(1288) PDF 3448KB(1746)

Abstract:
A statistical study has been conducted on all the geomagnetic storms caused by Coron Mass Ejection (CMEs) which are associated with flares from January 2010 to December 2012. The following results are obtained. The initial locations of CMEs mentioned above are distributed from 45°E to 45°W in solar longitude, accounting 78.95% of the total. Besides, the CMEs located in the west hemisphere are more likely to cause geomagnetic effects. X-class flares are more likely to be geo-effective, while flares in other classes have much lower probability. Geomagnetic storms will be observed in two or three days after 60% of X-class flares eruption. Therefore, more attention should been paid on X-class flares. By analyzing all the X-class flares erupted during this period, it is found that for the X-class flares located from 45°E to 45°W in solar longitude, if there is no disturbance on the solar surface (EUV wave) during eruption, the probability of the occurrence of geomagnetic storms after the flares will be very small. Therefore, a new method for geomagnetic storm forecasting by analyzing the Sun surface observations has been proposed.

Polynomial Solutions of the Ion Velocity Distributions and the Calculation of Incoherent Scatter Spectra in the High-latitude Auroral Ionosphere

XUE Kun, XU Zhengwen, WU Jian, ZHANG Yabin

2015, 35(4): 424-437. doi: 10.11728/cjss2015.04.424

Abstract(1897) PDF 927KB(8516)

Abstract:
In order to describe accurately ion velocity distribution in the auroral ionosphere, the relaxation collision model and the Maxwell molecule collision model is used to describe ion-neutral collisions of Boltzmann equation respectively. The expressions of the ion velocity distribution for 13-moment approximation based on the Maxwell and for 16-moment approximation based on the bi-Maxwell can be obtained by solving the transport equations of the Maxwell molecule collision model and the relaxation collision model respectively. According to Sheffield's theories, the incoherent scatter spectra are calculated using the ion velocity distribution of 13-moment approximation and 16-moment approximation for the relaxation collision model and the Maxwell molecule collision model respectively. Finally, the comparison of results of the incoherent scatter spectra between Maxwell molecule collision model and relaxation collision model are given. It is found that, the Maxwell molecule collision model is better than the relaxation collision model to describe the interaction between ion and neutral component in the ionosphere E layer. The 16-moment approximation is better than 13-moment approximation to describe the ion temperature anisotropy due to increased electric field.

Analysis and Results from ISR Observations of Lower Ionosphere

MA Xin, CHEN Gang, ZHONG Dingkun, ZHAO Zhengyu

2015, 35(4): 438-444. doi: 10.11728/cjss2015.04.438

Abstract(1924) PDF 3703KB(2408)

Abstract:
The D and E regions lie in the lower ionosphere region of 60～110km height. This region is influenced by solar radiation, cosmic noise radiation, atmospheric electrodynamics and many factors, and there exists a variety of incredible variation characteristics. Even in the magnetically quiet day, atmospheric electrodynamics can make a significant effect on this region except solar radiation. In the D region, there exists radio waves strong absorption, which can influence the transmission of high frequency radio waves. Electron and ion density can be obtained from the Incoherent Scatter Radar (ISR) Arecibo, located at Puerto Rico. ISR data can be used to study the movement characteristics of the lower ionosphere in mid-latitude, and get the electron density curves changing with time and height, which present obvious diurnal changing phenomenon. The spectrum of the data is analyzed to probe diurnal effects of electron density changes. Besides the electron density height profiles have been drawn, and observe obvious plasma descending from the base of F-layer to E region. The layer structure characteristics of the lower ionosphere and electron density changing show that there exists different degree of disturbance. By analyzing the influencing factors it is concluded that the atmospheric tides and the acoustic gravity waves can cause disturbance to lower ionosphere, which is coupled with the atmosphere in certain degree.

Nonlinear Interactions between the Quasi 5-day Wave and Tides Based on Meteor Radar Observations at Mauiormalsize

GU Jingxiao, HUANG Chunming, HUANG Kaiming

2015, 35(4): 445-452. doi: 10.11728/cjss2014.04.445

Abstract(1237) PDF 1663KB(1398)

Abstract:
Nonlinear interactions between the quasi 5-day wave and tides based on meteor radar observation in the Mesosphere and Lower Thermosphere (MLT) at Maui are studied in this paper. Strong sum interaction between quasi 5-day wave and diurnal tide, and evident difference interaction between quasi 5-day wave and semidiurnal tide are observed during the time of attention. However, their difference and sum counterparts are clearly weaker. The secondary waves generated from those interactions beat with the tide and show intense modulation at the period of 5 days which confirms the existence of their interactions. Additionally, correlation coefficients among these waves are calculated to further explore their interactions and find that they can persist for several days although they are highly intermittent. The energy exchange among these waves can be reversible during the observational time. The periods when the significant difference interaction between the quasi 5-day wave and semidiurnal tide occur are much shorter than those when the significant sum interaction between the quasi 5-day wave and diurnal tide occur. Moreover, these two strong interactions can take place simultaneously. In generally, this study provides the proof of nonlinear interactions between quasi 5-day wave and tides which were seldom reported before.

Gravity Wave Parameters and Their Seasonal Variations Derived from Na LidarObservations at Beijing

Zou Xu, Yang Guotao, Wang Jihong, Gong Shaohua, Cheng Xuewu, Jiao Jing, Yue Chuan, Fu Haichuan, Wang Zishuo, Yang Song, Yang Xianchang, Fu Jun

2015, 35(4): 453-460. doi: 10.11728/cjss2015.04.453

Abstract(1773) PDF 833KB(1248)

Abstract:
The nightly and seasonal variability of gravity wave activity and spectra in the mesopause over Beijing are studied with 3 years of sodium lidar observations. From the linear layer density response to gravity wave forcing, the lidar data were analyzed to get the atmospheric density perturbations and their spectra. The atmospheric density perturbation, density variance for fluctuations with vertical scales between 2 and 10 km, and amplitudes of density perturbation spectra at m = 2π/8, 2π/4, m = 2π/1.5, m = 2π/1, and ω = 2π/60, ω = 2π/40, 2π/25 all exhibit large nightly variability as well as large seasonal variations, with the semiannual maxima occurring near the solstice. The mean RMS atmospheric density perturbation over Beijing are 5.8%, which are obviously larger in summer than that in winter and the maxima occur near the solstice. The m spectra show power law shapes, and their range of variation is between -1.97 and -3.67 with an annual mean value of -3.02, and ω spectra is between -1.06 and -2.08 with an annual mean value of -1.92, respectively. It is concluded that the reaction of the Qinghai-Tibet Plateau and the background wind may be the main reason of the gravity wave behaviors at Beijing.

Statistical Analysis of Space Weather Effectson Satellites Anomalies

ZHANG Xiaofang, LIU Songtao, WU Yaoping

2015, 35(4): 461-472. doi: 10.11728/cjss2015.04.461

Abstract(2037) PDF 1655KB(2538)

Abstract:
Based on a large database of satellite anomalies containing 2384 anomalies from NGDC (USA) and 263 malfunctions from 19 satellites of China (CHN), and with a large set of hourly space weather condition parameters data over the period of 1963-2012, this paper quantifies statistically space weather conditions which may induce different spacecraft anomalies including Single Event Upset (SEU), Electrostatic Discharge (ESD) induced by surface charging, and Electron Caused Electromagnetic Pulse (ECEMP) resulting from internal, deep dielectric charging. The results are as follows. (1) Most anomalies of SEU, ECEMP occurred on quiet space conditions, whereas geomagnetic storms tended to happen during the 3 days (72h) before or after satellite anomalies started, and the most probable time for anomalies was on the third day (48～72h) after the minimum Dst (Dst_min). (2) Geomagnetic activities and high-energy electrons showed apparent effects on anomalies of ESD. Occurrence probabilities of ESD and ECEMP clearly increased in equinoxes (March, September), and such seasonal characteristic was consistent with that in occurrence probabilities of magnetic storms and Relativistic Electrons Flux Enhancement Events (REFEE). For 93.6% anomalies of ESD, geomagnetic storms tended to happen during 72h before, after ESD started, and the most probable occurring time was 0～48h before Dst_min or 0～24h after Dst_min. 54.9% anomalies occurred on geomagnetic conditions of Dst <-30nT, and intensities of storms seemingly influenced ESD little. 40.6% anomalies occurred at the time when the hourly >2MeV electron flux is above 10^3pfu (1pfu =1cm^-2·s^-1·sr^-1). For 81.9% anomalies of ESD, the hourly maximum of high-energy electron flux, during 72h before or after ESD started, was above 10^3pfu, and the most probable time interval was 48～72h before electron flux maximum, when 33.3% anomalies occurred. (3) High-energy electrons showed apparent effects on SEU of GEO from CHN database, 42.5% of anomalies occurring on conditions of electron flux ≥ 10³pfu. For those anomalies, the hourly maximum of > 2MeV electron flux exceeded 10³pfu during 72h before or after which started. The anomaly occurrence probabilities at the time of 48～72h before and 48～72h after electron flux maximum, were comparative, being about 23.0%. (4) Solar Proton Event (SPE) showed more influence on SEU of GEO. SPEs seemed no regular seasonal variations based on data during 1975-2013, while occurrence probabilities of SEUs showed little seasonal dependence. For 22.0% SEUs of GEO from CHN database, SPEs occurred during 72h before or after anomalies started, and SEUs might occur at any time of the 72h before or after the maximum of >10MeV proton flux.

Effect of LED on Plant Growth and Development in Space Culture Chamber Simulator

ZHANG Yue, PAN Jing, SUN Weining, ZHENG Huiqiong

2015, 35(4): 473-485. doi: 10.11728/cjss2015.04.473

Abstract(1859) PDF 1812KB(1228)

Abstract:
The goal of this study is to analyze the influence of LED light on the growth and development of plant in the plant culture chamber simulator for space experiment. The daylight fluorescence lamp was used as control to investigate the advantages and disadvantages of using LED in the plant cultivation, to provide reference data for the experiments of plant culture on board Chinese space lab TG-2 or space station in the near future. This paper focused on the influence of different LED conditions, e.g. spectra component, light intensity, light period and air exchange, on the growth of Arabidopsis thaliana and rice at different developmental stages. The results indicated that higher ratio of red to blue light could induce early flowering and early senescence in Arabidopsis and rice, respectively. The optimum ratio of red to blue light for the growth of Arabidopsis and rice is around 3.9. When the ratio is higher than 16, the growth of both Arabidopsis and rice was suppressed and leaf senescence was induced. In closed container, increased light intensity up to 150μmol·m^-2·s^-1 could partially release Arabidopsis growth inhibition caused by limited air exchange. When light intensity is higher than 150μmol·m^-2·s^-1, the growth and development of Arabidopsis were severely inhibited. For rice, the tolerance to high light was higher than Arabidopsis under limited air exchange conditions. Thus, the red to blue ligh ratios, light intensity and limited air exchange in microgravity environment should be considered when LED is used as light source in space plant culture chamber.

Method on Calculation of Lunar Soil Particles Trajectories Considering Collision Effect

ZHENG Gang, CUI Yuhong, YU Wei, REN Depeng, YE Qing, GENG Dongliang

2015, 35(4): 486-494. doi: 10.11728/cjss2015.04.486

Abstract(1622) PDF 2292KB(1178)

Abstract:
Regarding to the trajectory and mass distribution of lunar soil particles which are lifted by the lunar lander during the descending stage, a method considering the particles' collision effect is proposed. Based on the law of mass and energy conservation, the speed of regolith particles after collision is determined, and through the iterative calculations of fluid-structure interactions, the mass distribution caused both by collision effect and lunar lander effect on the lunar soil particles is presented. Through the measured data from the US Apollo 11 descending and landing on the lunar surface, the method are tested and verified by the numerical simulation. The analysis result shows that after the regolith particles colliding with each other having been considered, their trajectories have a more obvious tendency to spread. Furthermore, after the collision energy loss having been considered, the tendency to spread of regolith particles is weakened. And the smaller the coefficient of restitution is, the lower the raising height of the lunar soil particle will be.

Statistical Analysis of Space Debris's Parameters Based on the Incoherent Scattering Radar

DAI Li, ong, DING Zonghua, ZHAO Zhenwei, XU Zhengwen

2015, 35(4): 495-501. doi: 10.11728/cjss2015.04.495

Abstract(1672) PDF 6225KB(2258)

Abstract:
The ISR (Incoherent Scatter Radar) raw sampling data (time duration about 7 hours) is processed by Matching Filter (MF) method and totally 394 space debris are detected. Parameters including the height, radial velocity, Radar Cross-Section (RCS), effective diameter and radial velocity etc. are estimated, and statistical analysis about these parameters is made. The results show that the mean flux per hour through the radar beam is 60; the signal to noise ratio of space debris echo is above 10, which shows that the space debris is a strong target for ISR; the orbital height mainly is in two zones (600～1100km and 1400～1600km); the RCS is about 10^-5～10^-2m² and the effective diameter is about 3～10cm; the radial velocity is about -1.5～1.5km·s^-1; the radial acceleration is about 20～90m·s^-2. These results show the good perspective for ISR in the monitoring and forecasting of space debris.

Orbit Design for Twin-spacecraft Space VLBI

ZHANG Cheng, WU Xia, ZHENG Jianhua, WU Ji

2015, 35(4): 502-510. doi: 10.11728/cjss2014.04.502

Abstract(1339) PDF 3454KB(1143)

Abstract:
Space Very Long Baseline Interferometry (S-VLBI) is an aperture synthesis technique utilizing an array of radio telescopes including ground telescopes and space orbiting telescopes. It can achieve much higher spatial resolution than that from the ground-only VLBI. In this paper, a new concept of twin spacecraft S-VLBI has been proposed, which utilizes the space-space baselines formed by two satellites to obtain larger and uniform uv coverage without atmospheric influence and hence achieve high quality images with higher angular resolution. The orbit selections of the two satellites are investigated. The imaging performance and actual launch conditions are all taken into account in orbit designing of the twin spacecraft S-VLBI. Three schemes of orbit design using traditional elliptical orbits and circular orbits are presented. These design results can be used for different scientific goals. Furthermore, these designing ideas can provide useful references for the future Chinese millimeter-wave S-VLBI mission.

Process Optimization of Space Science Mission Concurrent Design

DENG Li, HAN Chao, CAO Jinbin

2015, 35(4): 511-518. doi: 10.11728/cjss2015.04.511

Abstract(1892) PDF 974KB(1234)

Abstract:
To optimize the process of space science mission concurrent design, an approach based on the Design Structure Matrix (DSM) modeling and Genetic Algorithm (GA) optimization method is proposed. In this approach, main design activities and dependencies relationship between the activities during the process of space science mission concurrent design are analyzed, and then the DSM model of the process is established. The design activities sequence corresponding to the DSM is treated as the chromosome and is optimized by the GA method. The optimal goal is to reduce the iterative times and to improve the parallel extent. A practical example of space science mission shows that the proposed approach can be applied to modeling and optimization of the process for space science concurrent design.

Analysis and Improvement of Lattice Reduction Based TH Precoding in MIMO Space Communications

JIANG Bin, BAO Jianrong, TANG Xianghong, ZENG Rong

2015, 35(4): 519-524. doi: 10.11728/cjss2015.04.519

Abstract(1170) PDF 597KB(995)

Abstract:
In order to evaluate and improve present precoding scheme in MIMO space communications, Zero-Force (ZF) and Minimum Mean Square Error (MMSE) criterion based joint Lenstra, Lenstra, Lovász (LLL) Lattice Reduction (LR) nonlinear Tomlinson-Harashima (TH) precoding algorithm is simulated and analyzed. At the same time, according to the basis of TH precoding, an improved lattice reduction based TH precoding is proposed by improving the singularity of the channel matrix. Simulation results indicate that the performance of MIMO precoding with MMSE criterion is better than that with ZF criterion. In addition, the proposed LLL lattice reduction based TH precoding has still obtained much better performance gain than traditional ones while a little more complexity is reduced by the LLL LR method. Therefore, it can be used in the precoding applications and so on in the multiple antenna MIMO space transmission.

2015 Vol. 35, No. 4

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